• Journal of the Korean Society for information Management
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• v.20 no.4 s.50
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• pp.23-48
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• 2003

In this study an information filtering system was implemented and a series of relevance feedback experiments were conducted using the system. For the relevance feedback, the original queries were searched against the database and the results were reviewed by the researchers. Based on users' online relevance judgements a pair of 17 refined queries were generated using two methods called 'co-occurrence exclusion method' and 'lower frequencies exclusion method,' In order to generate them, the original queries, the descriptors and category codes appeared in either relevant or irrelevant document sets were applied as elements. Users' relevance judgments on the search results of the refined queries were compared and analyzed against those of the original queries.

• Journal of the Korean Society of Food Culture
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• v.32 no.5
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• pp.373-382
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• 2017

This study investigated the nutrition knowledge, dietary habits, and food intake frequency according to hospitalization after breast cancer surgery and experience of breast cancer among female adults residing in the Bucheon area. Subjects were 52 female breast cancer survivors 27 in the hospitalization group (HG) and 25 in the non-hospitalization group (non-HG)] and 52 controls. Data included the results of self-administered questionnaires, as well as anthropometric data and blood biochemical values of breast cancer survivors collected from electronic medical records. Statistical analysis was performed using SPSS 20.0 program. Nutrition knowledge and dietary habits revealed no significant differences between HG and non-HG, but intake frequency of root and tuber crops and kimchi was significantly higher in the HG group than the non-HG group (p<0.05). According to experience of breast cancer, total scores of nutrition knowledge among survivors (8.2) were significantly higher than those of the control group (6.3) (p<0.001). Fish and shellfish and fruit intake frequencies were significantly higher in the survivors group, whereas intake frequency of fast food, convenience food, and alcohol was significantly lower compared to the control group. Overall, these findings indicate it is necessary to develop and spread nutrition education guidelines to prevent the occurrence and recurrence of breast cancer.

• Journal of Korean Society of Disaster and Security
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• v.13 no.3
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• pp.45-58
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• 2020

Due to a high portion of mountainous terrains in Korea, debris flow and its disasters have been increased. In addition, recently localized flash-floods caused by climate change should add frequencies and potential risks. Grasping and understanding the behaviors of debris flow would allow us to prevent the consequent disasters caused by its occurrence. In this study, we developed a number of cases by changing the bottom slopes and their curvatures and investigated their effects on potential damage caused by the debris flow using FLO-2D. As simulating each bed slopes we analyzed for velocity, depth, impact, reach distance, and reach shape. As a result the lower the average slope, the greater the influence of its curvature and the numerical results were analyzed with showed a well-marked difference in impact stress and flow velocity. The result from this study could be referred for protecting from the debris flows when design countermeasure structures in mountainous regions.

• Journal of the Korean Society of Hazard Mitigation
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• v.7 no.3
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• pp.41-49
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• 2007

In order to reduce the amount of damage from natural disasters and perform the natural disaster mitigation program, the prevention activities and forecasting based on meteorological parameters and disaster datas are required. In addition, it is necessary to process prevention meteorological information for prevention activities in advance. For this, we have analyzed four data, such as Statistical yearbook of calamities and Statistics Yearbook issued by the Ministry of Government Administration and Human affairs. And Annual Climatological Report issued by the Korea Meteorological Administration and Recently 10 years for natural disaster damage from the Central Disaster and Safety Countermeasures Headquarters. We analyzed the causes, elements, occurrence frequencies, and vulnerable areas of natural disaster, using the 4 disaster datas, but these datas was not consistent with their terminology and items. Through the analysis of a kind and damage of disaster, we have selected the disaster variables, such as causes and elements, the amount of damage, vulnerable areas of natural disaster, etc and made a database. This database will be used to assess the natural disasters and develop the risk model and natural disasters mitigation plan.

• Composites Research
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• v.16 no.6
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• pp.16-22
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• 2003

This paper studied the AE(acoustic emission) characteristics of the laminated composite structures. The composite stiffened panels under the compressive loading emitted various AE signals when they buckled or changed the buckling modes. In addition, the failure initiated and propagation generated a lot of complex signals. From the continuous signal generation. we identified when the failures initiated and whether they propagated or not. The single lap joint of laminated plates under tensional load also generated AE signals when bonding region failed. The first failure occurrence and its propagation are monitored by generated AE signals. The characteristics of AE signals used in this analysis are cumulative hits, hit distribution, peak frequency of generated AE waveform and amplitude of signals. The analysis of AE signals shows that continuous increment of cumulative hits can be regarded as damage propagation and three dominant peak frequencies can correspond to typical failure modes in the laminated composites.

• Structural Engineering and Mechanics
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• v.25 no.4
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• pp.481-500
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• 2007

The dynamic instability of doubly curved panels, subjected to non-uniform tensile in-plane harmonic edge loading $P(t)=P_s+P_d\;{\cos}{\Omega}t$ is investigated. The present work deals with the problem of the occurrence of combination resonances in contrast to simple resonances in parametrically excited doubly curved panels. Analytical expressions for the instability regions are obtained at ${\Omega}={\omega}_m+{\omega}_n$, (${\Omega}$ is the excitation frequency and ${\omega}_m$ and ${\omega}_n$ are the natural frequencies of the system) by using the method of multiple scales. It is shown that, besides the principal instability region at ${\Omega}=2{\omega}_1$, where ${\omega}_1$ is the fundamental frequency, other cases of ${\Omega}={\omega}_m+{\omega}_n$, related to other modes, can be of major importance and yield a significantly enlarged instability region. The effects of edge loading, curvature, damping and the static load factor on dynamic instability behavior of simply supported doubly curved panels are studied. The results show that under localized edge loading, combination resonance zones are as important as simple resonance zones. The effects of damping show that there is a finite critical value of the dynamic load factor for each instability region below which the curved panels cannot become dynamically unstable. This example of simultaneous excitation of two modes, each oscillating steadily at its own natural frequency, may be of considerable interest in vibration testing of actual structures.

• The Journal of the Acoustical Society of Korea
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• v.37 no.2
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• pp.92-98
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• 2018

This paper is a study on the generation mechanism of propeller singing based on the cavitation tunnel test, underwater impact test, finite element analysis and computational flow analysis for the model propeller. A wire screen mesh, a propeller and a rudder were installed to simulate ship stern flow, and occurrence and disappearance of propeller singing phenomenon were measured by hydrophone and accelerometer. The natural frequencies of propeller blades were predicted through finite element analysis and verified by contact and non-contact impact tests. The flow velocity and effective angle of attack for each section of the propeller blades were calculated using RANS (Reynolds Averaged Navier-Stokes) equation-based computational fluid analysis. Using the high resolution analysis based on detached eddy simulation, the vortex shedding frequency calculation was performed. The numerical predicted vortex shedding frequency was confirmed to be consistent with the singing frequency and blade natural frequency measured by the model test.

• Journal of Technologic Dentistry
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• v.11 no.1
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• pp.103-109
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• 1989

Bond strength between alloy and ceramic plays an important role in deciding the quaring the processing of metalceramic restorations. Now the author had an experiment on the measurement of bond strength differences accoding to the contents of recast alloy used during the processing of metal-ceramic restorations. In the experiment, Anusavice's Planar Interface Shear Bond Test was employed to determine the bond strength. Total 25 specimens were divided as 5 groups, that is, 5 specimens in a group respections : Group I (new alloy 100%) Group II (new 75%$\cdot$recast 25%), Group III (new 50%$\cdot$recast 50%), Group IV (new 25%$\cdot$recast 75%), Group V(recast 100%). All specimens examined micropically and respective strength values of the group specimens were checked simultaneously. The results were as follows, 1. In the analtsis of variance the result showed the significant differences of 1%(P<0.01) among the each group classifid according to the recast contents. 2. When the interfaces of specimens were examined with an electron microscope, the air bubble were evenly occurred in all the specimens, and the occurrence frequencies and the sizes of air bubble were different between Group I and Group III, especially marked different Group I and Croup V. 3. In respective verification of each group through T-test, between Group I and Group II, between Group I and Group III did not show significant differences. 4. There was significant difference between Group I and Group IV, between Group I and Group V as 1%(P<0.01). 5. In the Shear Bond Test of all the groups, Croup V showed the lowest value. Explanatoion of Figures Fig 1. Main fracture type of metal-porcelain interlace showed in group I, II, III from shear Bond Test resets. Fig 2. Main fracture type of metal-porcelain interface showed In group Ⅳ, Ⅴ form shear Bond Test resets. Air bubble and their size appeared around interface of metal-porcelain. Fig 3. Group I, Fig 4. Group II Fig 5. Group III, Fig 6. Group IV, Fig 7. Group V.

• The KIPS Transactions:PartB
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• v.10B no.3
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• pp.347-358
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• 2003

VSField-associated term is a single or compound word whose terms occur in any document, and which makes it possible to recognize a field of text by using common knowledge of human. For example, human recognizes the field of document such as or , a field name of text, when she encounters a word 'Pitcher' or 'election', respectively We Proposes an efficient construction method of field-associated terms (FTs) for specializing field to decide a field of text. We could fix document classification scheme from well-classified document database or corpus. Considering focus field we discuss levels and stability ranks of field-associated terms. To construct a balanced FT collection, we construct a single FTs. From the collections we could automatically construct FT's levels, and stability ranks. We propose a new extraction algorithms of FT's for document classification by using FT's concentration rate, its occurrence frequencies.

• Genomics & Informatics
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• v.7 no.4
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• pp.187-194
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• 2009

Cytochrome P450 2E1 (CYP2E1) is a member of the cytochrome P450 superfamily, and it is a key enzyme responsible for the metabolic activation of many smallmolecular-weight compounds such as alcohol, which is classified as a human carcinogen. In this study, we identified 19 single nucleotide polymorphisms (SNPs) in CYP2E1 in Korean population. In these SNPs, we examined possible genetic association of CYP2E1 polymorphisms with HBV clearance and the risk of hepatocellular carcinoma (HCC). Five common polymorphic sites were selected, CYP2E1 polymorphisms at rs381-3867, rs3813870, rs2070673, rs2515641 and rs2480257, considering their allele frequencies, haplotype-tagging status and LDs for genotyping in larger-scale subjects (n=1,092). Statistical analysis demonstrated that CYP2E1 polymorphisms and haplotypes show no significant association with HBV clearance, HCC occurrence and onset age of HCC (p>0.05). Previous studies, however, have shown contradictory findings on associations of CYP2E1 polymorphisms with CYP2E1 activities and HCC risk. Comparing the contrasting results of previous researches suggest that CYP2E1 polymorphism is associated with CYP2E1 activity induced by ethanol, but is not directly associated with HCC risk. CYP2E1 variation/haploype information identified in this study will provide valuable information for future studies on CYP2E1.